package org.adream.account.util;

import org.apache.commons.codec.binary.Base64;
import javax.crypto.Cipher;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

public class RSACoderUtil {
	
	public static RSACoderUtil instance = new RSACoderUtil();
	
	private static String PUBLIC_KEY = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCJQflcyxd5GTjsVpMG0AlFn0ErAn30GpV1vUqsa+VFZI61HtvV+30lvBt66lEMY4XHERP7kDtW/WrwngLt4tMpawSX+VlFc8D31dnSBEILoqQKtiUe4BZk7l3dX+lF3hiHHTE3+YLQ/vI50zT1CSUrDiMwwoLSgyBxlvCaBwssywIDAQAB";
	private static String PRIVATE_KEY = "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";

	/** 
	 * 随机生成密钥对 
	 * @throws NoSuchAlgorithmException 
	 */  
	public Map<Integer, String> initKey() throws NoSuchAlgorithmException {  
		Map<Integer, String> keyMap = new HashMap<Integer, String>();
		// KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象  
		KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");  
		// 初始化密钥对生成器，密钥大小为96-1024位  
		keyPairGen.initialize(1024,new SecureRandom());  
		// 生成一个密钥对，保存在keyPair中  
		KeyPair keyPair = keyPairGen.generateKeyPair();  
//		RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();   // 得到私钥  
//		RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();  // 得到公钥  
	//	String publicKeyString = new String(Base64.encodeBase64(publicKey.getEncoded()));  
		// 得到私钥字符串  
	//	String privateKeyString = new String(Base64.encodeBase64((privateKey.getEncoded())));  
		// 将公钥和私钥保存到Map
		keyMap.put(0,PUBLIC_KEY);  //0表示公钥
		keyMap.put(1,PRIVATE_KEY);  //1表示私钥
		return keyMap;
	}  
	/** 
	 * RSA公钥加密 
	 *  
	 * @param str 
	 *            加密字符串
	 * @param publicKey 
	 *            公钥 
	 * @return 密文 
	 * @throws Exception 
	 *             加密过程中的异常信息 
	 */  
	public String encrypt( String str, String publicKey ) throws Exception{
		//base64编码的公钥
		byte[] decoded = Base64.decodeBase64(publicKey);
		RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
		//RSA加密
		Cipher cipher = Cipher.getInstance("RSA");
		cipher.init(Cipher.ENCRYPT_MODE, pubKey);
		String outStr = Base64.encodeBase64String(cipher.doFinal(str.getBytes("UTF-8")));
		return outStr;
	}

	/** 
	 * RSA私钥解密
	 *  
	 * @param str 
	 *            加密字符串
	 * @param privateKey 
	 *            私钥 
	 * @return 铭文
	 * @throws Exception 
	 *             解密过程中的异常信息 
	 */  
	public String decrypt(String str, String privateKey) throws Exception{
		//64位解码加密后的字符串
		byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8"));
		//base64编码的私钥
		byte[] decoded = Base64.decodeBase64(privateKey);  
        RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));  
		//RSA解密
		Cipher cipher = Cipher.getInstance("RSA");
		cipher.init(Cipher.DECRYPT_MODE, priKey);
		String outStr = new String(cipher.doFinal(inputByte));
		return outStr;
	}
   
}
